This project is concerned with two important areas of lipid and protein metabolism, namely blood coagulation and myelination. In the coagulation project attention is directed specifically to the mechanism of conversion of prothrombin to thrombin. This latter reaction is catalyzed by complex composed of two plasma proteins, factor Xa, factor V, phospholipid and Ca plus 2. An important facet of this study to elucidate the route by which these various components actually amplify the activity of the protease, factor Xa, towards prothrombin. Attention is being directed towards purification of all these proteins from human as well as bovine plasma, and the synthesis of phospholipids containing fatty acyl chains ranging from C6 to C18. In the myelination research program, attention is being directed towards the study of the onset of myelination in the rat optic nerve and also phospholipid biosynthesis in the brain. Inasmuch as an ultracentrifuge technique can be used to detect myelin, it is planned now to attempt to manipulate conditions such as to identify the factors important in initiation. Phospholipid biosynthesis in the developing brain is peculiar since the two major components, phosphatidyl choline and phosphatidyl ethanolamine, share no fatty acyl species in common, which would be demanded by currently accepted biosynthetic routes. It is planned to direct this research study to subcellular localization of species and characterization of the enzymes involved in the biosynthesis.